chore(accounting): PR #622 nits — stray artifact, dedupe requireFlag, IMAP poll backoff

1. Remove the committed test artifact backend/storage/business-docs/quote/2026/
   Q-2026-0001.pdf and gitignore backend/storage/business-docs/ so generated CRM
   docs can't be committed again.
2. adminLedger + adminExpenses dropped their local requireFlag copies and now
   import the shared (now cached) requireFeatureFlag middleware.
4. roundTripTest polls IMAP with ×1.5 backoff (cap 8s) instead of a flat 3s, so a
   30s test takes ~5 SELECT/SEARCH locks not ~10 (some servers throttle).

Nit 3 (dashboard + events pages still on the gallery-theme vars, not dark-mode-
swapped) is left as a documented follow-up per the review.

backend/src/routes/adminExpenses.js

@@ -48,19 +48,11 @@ function diskUpload(subdir) {
 const inboundUpload = diskUpload('inbound');
 const proofUpload = diskUpload('expenses/proof');
 
-function requireFlag(key, code) {
-  return async (req, res, next) => {
-    try {
-      const row = await db('feature_flags').where({ key }).first();
-      const enabled = row && (row.value === true || row.value === 1 || row.value === '1');
-      if (!enabled) return res.status(403).json({ error: `${key} feature is disabled`, code });
-      return next();
-    } catch (err) { return next(err); }
-  };
-}
-const requireIncoming = requireFlag('incomingInvoices', 'INCOMING_INVOICES_DISABLED');
-const requireExpenses = requireFlag('expenses', 'EXPENSES_DISABLED');
-const requireAccounting = requireFlag('accounting', 'ACCOUNTING_DISABLED');
+// Shared cached feature gate (PR #622 nit 2) — replaces the former local copy.
+const { requireFeatureFlag } = require('../middleware/requireFeatureFlag');
+const requireIncoming = requireFeatureFlag('incomingInvoices', 'INCOMING_INVOICES_DISABLED');
+const requireExpenses = requireFeatureFlag('expenses', 'EXPENSES_DISABLED');
+const requireAccounting = requireFeatureFlag('accounting', 'ACCOUNTING_DISABLED');
 
 router.use(adminAuth);
 

backend/src/routes/adminLedger.js

@@ -21,17 +21,9 @@ const ledgerService = require('../services/ledgerService');
 const router = express.Router();
 const toInt = (v) => { const n = parseInt(v, 10); return Number.isFinite(n) ? n : undefined; };
 
-function requireFlag(key, code) {
-  return async (req, res, next) => {
-    try {
-      const row = await db('feature_flags').where({ key }).first();
-      const enabled = row && (row.value === true || row.value === 1 || row.value === '1');
-      if (!enabled) return res.status(403).json({ error: `${key} feature is disabled`, code });
-      return next();
-    } catch (err) { return next(err); }
-  };
-}
-const requireAccounting = requireFlag('accounting', 'ACCOUNTING_DISABLED');
+// Shared cached feature gate (PR #622 nit 2) — replaces the former local copy.
+const { requireFeatureFlag } = require('../middleware/requireFeatureFlag');
+const requireAccounting = requireFeatureFlag('accounting', 'ACCOUNTING_DISABLED');
 
 router.use(adminAuth);
 router.use(requireAccounting);

backend/src/services/emailIntakeService.js

@@ -202,6 +202,9 @@ async function roundTripTest({ timeoutMs = 30000, intervalMs = 3000 } = {}) {
   const client = makeImapClient(cfg);
   await connectWithTimeout(client);
   const started = Date.now();
+  // Backoff (PR #622 nit 4): some IMAP servers throttle frequent SELECT/SEARCH.
+  // Grow the gap ×1.5 (cap 8s) so a 30s test does ~5 polls, not ~10.
+  let delay = intervalMs;
   try {
     // eslint-disable-next-line no-constant-condition
     while (true) {
@@ -219,7 +222,8 @@ async function roundTripTest({ timeoutMs = 30000, intervalMs = 3000 } = {}) {
         return { ok: false, sent: true, reason: 'not_received', recipient };
       }
       // eslint-disable-next-line no-await-in-loop
-      await new Promise((r) => setTimeout(r, intervalMs));
+      await new Promise((r) => setTimeout(r, delay));
+      delay = Math.min(Math.round(delay * 1.5), 8000);
     }
   } finally {
     await client.logout().catch(() => {});

backend/storage/business-docs/quote/2026/Q-2026-0001.pdf

@@ -1 +0,0 @@
-pdf